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Circuit/System Testing

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

C025E 71

  1. Ignition ON.
  2. Verify that no other DTCs are set.
    • If no other DTCs are set 
  3. Replace the K20 Engine Control Module.
  4. Verify the DTC C025E does not set while operating the vehicle under the conditions for Running the DTC.
    • If the DTC sets 

      Replace the K17 Electronic Brake Control Module.

    • If the DTC does not set 
  5. All OK.

C025E 01, C025E 04, C025E 5A, C027B 01, or C027B 04

  1. Ignition OFF and all vehicle systems OFF, disconnect the KR14 Brake Booster Pump Motor Relay. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal 1 (86) and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal 3 (30) and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for infinite resistance between the control circuit terminal 5 (87) and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the KR14 Brake Booster Pump Motor Relay.
    • If the test lamp illuminates 
  5. Connect a test lamp between the control circuit terminal 2 (85) and the ground circuit terminal 1 (86). Clear EBCM DTCs.
  6. Verify the test lamp turns ON and OFF when commanding the Brake Booster Electric Vacuum Pump ON and OFF with a scan tool.
    • If the test lamp is always OFF  
    1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
    2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K17 Electronic Brake Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module, ignition ON.
    2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K17 Electronic Brake Control Module.
    • If the test lamp turns ON and OFF 
  7. Verify that a test lamp does not illuminate between the control circuit terminal 5 (87) and ground.
    • If the test lamp illuminates  

      Repair the short to voltage on the control circuit

    • If the test lamp does not illuminate 
  8. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M9 Brake Booster Pump Motor. It may take up to 2 min for all vehicle systems to power down.
  9. Test for less than 10 Ω between the M9 Brake Booster Pump Motor ground circuit terminal 2 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  10. Connect the harness connector at the M9 Brake Booster Pump Motor.
  11. Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 3 (30) and the control circuit terminal 5 (87) .
  12. Verify the M9 Brake Booster Pump Motor is activated.
    • If the M9 Brake Booster Pump Motor does not activate 
    1. Ignition OFF, disconnect the harness connector at the M9 Brake Booster Pump Motor.
    2. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the M9 Brake Booster Pump Motor.
    • If the M9 Brake Booster Pump Motor activates 
  13. Test for 60-180 Ω between terminals 85 and 86 on the relay.
    • If less than 60 or greater than 180 Ω 

      Replace the relay.

    • If between 60-180 Ω 
  14. Test for infinite resistance between the terminals listed below:
    • 30 and 86
    • 30 and 85
    • 30 and 87
    • 85 and 87
    • If less than infinite resistance 

      Replace the relay.

    • If infinite resistance 
  15. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground.
  16. Test for less than 2 Ω between terminals 30 and 87.
    • If 2 Ω or greater  

      Replace the relay.

    • If less than 2 Ω 
  17. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B19B Brake Booster Vacuum Sensor. It may take up to 2 min for all vehicle systems to power down.
  18. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K17 Electronic Brake Control Module.
    • If less than 10 Ω 
  19. Ignition ON.
  20. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
    2. Test for infinite resistance between the 5 V reference circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the 5 V reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K17 Electronic Brake Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module, ignition ON.
    2. Test for less than 1 V between the 5 V reference circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K17 Electronic Brake Control Module.
    • If between 4.8-5.2 V 
  21. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module, Ignition ON.
  22. Test for less than 1 V between the B19B Brake Booster Vacuum Sensor signal circuit terminal 1 and ground.
    • If greater than 1 V 

      Repair the short to voltage on the circuit.

    • If less than 1 V 
  23. Ignition OFF.
  24. Test for infinite resistance between the B19B Brake Booster Vacuum Sensor signal circuit terminal 1 and ground.
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • If infinite resistance 
  25. Test for less than 2 Ω in the B19B Brake Booster Vacuum Sensor signal circuit end to end.
    • If 2 Ω or greater 

      Repair the open/high resistance in the circuit.

    • If less than 2 Ω 
  26. Replace the B19B Brake Booster Vacuum Sensor.
  27. Verify the DTC does not set while operating the vehicle under Conditions for Running the DTC.
    • If the DTC sets 

      Replace the K17 Electronic Brake Control Module.

    • If the DTC does not set 
  28. All OK.
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